Honing stone



Sept. 15, 1959 e. R. ELDRED 2,903,828

HONING STONE Filed Jan. 15. 1958 J ZZE-L- g,

INVENTOR. 6:90 rye ,3, ZZZ/r64 United States Patent HONING STONE George R. Eldred, Pontiac, Mich., assignor to Micromatic Hone Corporation, Detroit, Mich, a corporation of Michigan Application January 13, 1958, Serial No. 708,418

4 Claims. (Cl. 51-204) This invention relates to honing stones and particularly to an abrading stone and the supporting structure therefor.

An object of the present invention is to provide a mounting for an abrading stone which is of a sturdy and rigid construction, firmly supporting the stone by a simple and inexpensive construction.

Another object of the present invention is to provide mounting structure for a honing stone which leaves the leading edge of the abrading surface thereof exposed to the work and thereby enhances the gradual and continuous break down of the abrading surface, and prevents the build up of material on the working surface which would impair the grinding efliciency of the stone.

An additional object of the present invention is to provide a honing stone mounting structure which readily secures the stones to a honing tool for replacement of stones worn out from use.

Other objects and features of novelty of the invention will be specifically pointed out or otherwise become apparent when referring, for a better understanding of the invention, to the following description taken in conjunction with the accompanying drawing, wherein:

Figure 1 is a front elevational view of a honing stone assembly embodying the present invention;

Fig. 2 is a plan view of the structure illustrated in Fig. 1;

Fig. 3 is a right hand end view of the structure i1- lustrated in Fig. 3.

Fig. 4 is a view of the stone supporting member of the assembly illustrated in Fig. 1;

Fig. 5 is a right hand end view of the structure illustrated in Fig. 4; and

Fig. 6 is an exploded perspective view of the structure illustrated in Figs. 1 to 3.

The improved honing stone assembly of the present invention utilizes a bonded abrasive stone 11 of the usual elongated rectangular shape. The stone has a bottom surface 13 and a top Working surface 15, spaced by front front and rear faces 24 and 25. The abrasive stone 11 is mounted on and carried by a supporting member 17 which is constructed from a rectangular sheet of material and which is formed to have a web 19 with flanges 21 and 23 extending in opposite directions from the side edges thereof at right angle relation thereto. The abrasive stone 11 is fixedly secured to the supporting member 17 by a suitable adhesive material applied to the inner surfaces of the web 19 and flange 21 which are engaged by the bottom surface 13 and rear wall 25 of the stone 11. The longitudinal extremity 27 of the flange 21 terminates at an edge 29 of the working surface 15, which constitutes the trailing edge of stone 11 when the same is rotated during use. The length of flange 21 is coextensive with the length of the stone 11 and thus the flat area of the flange 21 and the rear wall 25 of the stone 11 are coextensive.

The assembled abrasive stone 11 and supporting member 17 is designed to be mounted on a supporting bar 31 which forms a detachable component of a honing tool designed to hone the bores of cylinder blocks and the like. The supporting bar 31 is formed from a section of solid stock and is of rectangular cross section. A supporting surface 33 of the bar is located intermediate of integrally formed spaced flanges 35 and 37 near the ends of the bar. Spaced grooves 39 and 41 are formed in the ends 43 and 45 of the bar, beyond the flanges 35 and 37, respectively. A threaded aperture 47 extends transversely through the bar 31 parallel to surface 33 and through a boss 48 extending rearwardly from the trailing side of the bar.

The mounting bars 31 are supported in vertical slots in a honing tool body by garter springs (not shown) which engage the grooves 39 and 41 and which permit the bars stones to be radially adjusted.

The assembled supporting member 17 and stone 11 is mounted on the bar 31 with the web 19 of the clip resting on the supporting surface 33. The distance between the flanges 35 and 37 is substantially the length of the member 17 so as to prevent lengthwise movement of the member 17 on the bar 33. The member 17 is held to the bar by a screw 49 extending through an aperture 51 formed in the flange 23 of the member 17 and into the threaded aperture 47. The aperture 51 is so positioned as to be aligned with the aperture 47 when the parts are assembled as shown in Fig. 1.

The supporting member 17 is preferably formed of rigid nonferrous material which is relatively soft. Thus aluminum or brass are satisfactory when the tool is used to hone the bore of an engine block. As the working surface 15 of the stone 11 breaks down, the edge 27 of the flange 21 is abraded sufiiciently so as not to interfere with the abrading action of the stone face 15 with the wall'of the bore being honed. The metal of the member 17 is substantially softer than the metal of the bore wall, and therefore will not damage the wall, yet it is of sufli cient rigidity to adequately support the honing stick 11 in its working position as it wears away with the face of the stone. 7

It has been found that the initial use of the abrading stone 11 may be enhanced by beveling the rear portion of the working surface 15, as illustrated by the figure 52 in Figs. 3 and 5. During initial use, the abrading surface 15 coming into contact with the cylinder bore wall being honed will assume the shape of the surface being honed. Thus the working surface 15 will become curved in cross section and its center will be higher than its edges. By initially positioning the edge 27 of flange 21 below the center of working surface 15, the working surface 15 will more quickly assume its curved configuration and thus more readily achieve total engagement with the bore wall.

In the operation of the honing tool in which the present honing element is used, the tool is moved in rotation and reciprocation, the rotation occurring in the direction of the arrow illustrated in Fig. 5 having the corner 53 the leading edge of the stone. It will be noted that the structure of the member 17 leaves the leading edge 53 and the face 24 therebelow of the working surface 15 in an exposed unsupported condition. The leading edge 53 is thus subjected to a force in compression rather than one in tension as is present at the trailing edge 29. It is well known that a bonded abrasive stone is capable of withstanding substantial compression pressure but is extremely weak when subjected to tensional strain. For this reason the member 17 affords supporting strength to the stone 11 at the places where it is needed. In addition it has been found that for certain honing operations the absence of any substantial supporting material from the leading edge of the stone is a distinct advantage. In order to hone efliciently the working surface of the stone must continuously undergo a minute but steady breakdown, losing the dulled particles of abrasive material along its Working surface. Otherwise, the working surface of the stone would become smooth and loaded with particles of the surface material being honed which would impair the efliciency of the honing operation. A continual break down of the abrading particles of the honing stone surface will result in the most eifective honing operation. This breakdown process begins at the leading edge of the stone and when the leading edge and face is unrestricted this break down process is unhindered.

, A light coating of non-abrasive plastic 55 is sprayed or otherwise applied to the face 24 for purposes of preventing abrasion of the recesses in the hon g tool within .which the assembled stone and supporting member is moved during the honing operation. However, the material 55 is of an unsubstantial nature and will easily abrade away along the leading edge 53 during use and offers no significant support to the stone 11. It will thus be seen that the presence of such a material on the stone 11 does not obviate the advantage obtained by leaving the surface 24 free of any substantial supporting element.

What is claimed is:

1. In an abrading element for a honing tool, an elongated abrading stone having two adjacent substantially perpendicular faces extending the length thereof, a supporting member for said honing stone formed from a single section of sheet material which is bent to form a web portion from the opposite edges of which flanges extend in opposite directions in substantially right angle relation to said web portion, adhesive means for retaining said honing stone fixed to said supporting member With the adjacent surfaces of said honing stone abutting said web portion and one of said flanges, and means associated with the other of said flanges for retaining said supporting member fixed to a movable honing tool element.

2. In an abrading element for a honing tool, an elongated honing stone of substantially rectangular cross section, a supporting member for said stone formed from a rectangular section of sheet material of a length substantially equal to the length of said stone and being bent along its length to provide a, web portion and oppositely extending flanges on either side thereof disposed at substantially right angle relation to said web portion, means for holding said stone in abutting relation with said web portion and one of said flanges, and means associated with the other of said flanges for securing said supporting member to a radially movable element of a honing tool.

3, In an abrading element for a honing tool, an elongated honing stone of substantially rectangular cross section, a supporting member for said stone of a length substantially equal to the length of said stone and having a Web portion and oppositely extending integral flange portions on either side thereof disposed at substantially rightangle relation to said web portion, said stone being retained in abutting relation with said web portion and one of said flange portions, and means associated with the other of said flange portions for securing said supporting member to a radially movable element of a honing tool.

4. In an abrading element for a honing tool, an elongated honing stone of substantially rectangular cross section, a supporting member for said stone of a length substantially equal to the length of said stone, said supporting member being comprised of three integral substantially rectangular sections including a central section and two outer sections extending in opposite directions from opposite edges of said central section and disposed at right angles to said central section, said stone being retained in abutting relation with said central section and one of said outer sections, and aperture means in the other of said sections for securing said supporting member to a radially movable honing element.

References Cited in the file of this patent UNITED STATES PATENTS 

